NAME

       Rex::Transaction - Transaction support.

DESCRIPTION

       With this module you can define transactions and rollback scenarios on failure.

SYNOPSIS

        task "do-something", "server01", sub {
          transaction {
            on_rollback {
              rmdir "/tmp/mydata";
            };

            mkdir "/tmp/mydata";
            upload "files/myapp.tar.gz", "/tmp/mydata";
            run "cd /tmp/mydata; tar xzf myapp.tar.gz";
            if($? != 0) { die("Error extracting myapp.tar.gz"); }
          };
        };

EXPORTED FUNCTIONS

   transaction($codeRef)
       Start a transaction for $codeRef. If $codeRef dies it will rollback the transaction.

        task "deploy", group => "frontend", sub {
           on_rollback {
             rmdir "...";
           };
           deploy "myapp.tar.gz";
        };

        task "restart_server", group => "frontend", sub {
           run "/etc/init.d/apache2 restart";
        };

        task "all", group => "frontend", sub {
           transaction {
             do_task [qw/deploy restart_server/];
           };
        };

   on_rollback($codeRef)
       This code will be executed if one step in the transaction fails.

       See transaction.